The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical multi-speed automatic transmission uses a combination of torque transmitting devices, such as clutches or brakes, to achieve a plurality of forward and reverse gear or speed ratios as well as a Neutral and a Park. Selection of speed ratios is typically accomplished by a microprocessor transmission control module that employs various vehicle parameters, for example vehicle speed, and various driver input signals, for example accelerator pedal position, to select the appropriate speed ratios. The transmission then engages a combination of the toque transmitting devices to provide the desired speed ratios.
In order to engage the torque transmitting devices, a typical automatic transmission includes a hydraulic clutch control system that employs a hydraulic fluid to selectively actuate pistons within the torque transmitting devices. Actuation of a piston in turn engages the torque transmitting elements (i.e., friction discs and metal plates) within the torque transmitting device.
In all transmission types, axial length of the transmission (i.e. axial packaging) is an important design consideration. For example, hybrid transmissions have an electric motor located along the axis of the transmission that is coupled to a torque transmitting device. Accordingly, the length of the electric motor and the torque transmitting device within the transmission directly impacts the axial length of the powertrain. One solution to limiting the length of the powertrain is to limit the length of the electric motor. However, this may impact the motor torque output of the electric motor and impact vehicle performance. Accordingly, there is a need in the art for a compact torque transmitting device that operates effectively and smoothly that reduces the axial length of the transmission which in turn eliminates the need to reduce the axial length of other components within the transmission.